Method for applying an inorganic titanium coating to a glass surface

ABSTRACT

An inorganic titanium coating believed to be a titanium oxide coating is applied to a glass surface by exposing the surface at elevated temperature, desirably at least 300*F., to a liquid comprising a titanium oxychloride of the formula Ti(OH)xCl(4 x) wherein x is 1, 2 or 3, for example an aqueous solution of a titanium oxychloride. The process is especially useful for providing the &#39;&#39;&#39;&#39;hot end coating&#39;&#39;&#39;&#39; of a dual protective coating for glass containers comprising an inorganic &#39;&#39;&#39;&#39;hot end coating&#39;&#39;&#39;&#39; and a lubricious organic &#39;&#39;&#39;&#39;cold end coating&#39;&#39;&#39;&#39;.

United States Patent [1 1 Smay et al.

[ Dec. 16, 1975 METHOD FOR APPLYING AN INORGANIC TITANIUM COATING TO AGLASS SURFACE [75] Inventors: Gary Lynn Smay, Butler; Ronald VanCaporali, West Sunbury;

Russell Duty Southwick, Butler, all of Pa.

[73] Assignee: Glass Container Manufacturers Institute, Inc.,Washington, DC.

[22] Filed: Feb. 19, 1974 [21] Appl. No.: 443,227

[52] US. Cl. 65/60; 423/462; 427/226; 427/407; 427/419; 427/421; 427/427[51] Int. CL C03C 17/22; BOSD l/36; B05D 3/02; 805D l/02 [58] Field ofSearch 423/462; 117/124 T, 72, l17/94, 124 A, 124 B, 124 D, 124 E; 65/60[56] References Cited UNITED STATES PATENTS 2,831,780 4/1958 Deyrup117/124 B 3,004,863 l0/l96l Gray 117/124 A 3,323,889 6/1967 Carl 117/943,387,994 6/1968 Danton 117/94 3,414,429 l2/1968 Bruss 117/88 7/1970Russell 117/124 T 6/1972 Green 117/124 D OTHER PUBLICATIONS ChemicalAbstracts, Vol. 60: 1.5468a. Chemical Abstracts, Vol. 78: 165198147-273.

Mellor, A Comprehensive Treatise on Inorganic and Theoretical Chemistry,V01. V11, pp. 82-83. 1927.

Primary Examiner-William D, Martin Assistant ExaminerWilliam H. SchmidtAttorney, Agent, or FirmKenyon & Kenyon Reilly Carr & Chapin 5 7]ABSTRACT ing 8 Claims, N0 Drawings METHOD FOR APPLYING AN INORGANICTITANIUM COATING TO A GLASS SURFACE This invention relates to animproved method for applying an inorganic titanium coating to a glasssurface. More particularly, this invention is concerned with an improvedmethod for applying an inorganic titanium hot end coating to a glasscontainer.

BACKGROUND OF THE INVENTION It has long been known that inorganiccoatings can be applied to a glass surface by contacting a hot glasssurface with a thermally-decomposable metallic compound, whereby thecompound, when brought in contact with the hot glass, decomposes to formwhat is believed to be a metal oxide layer on the surface of the hotglass. Processes of this type were disclosed by Lyle in U.S. Pat. No.2,375,482 for imparting an iridescent finish to glass.

More recently, processes of this type have been adapted for use inprotective coatings for glass containers, particularly beverage bottlesand other similar containers. In these processes glass containers, suchas glass bottles, while still hot from the bottle-forming equipment andbefore passage through the annealing lehr, are treated with athermally-decomposable metal compound, usually stannic chloride, underconditions such that a thin coating is formed on the container surface.This coating is thinner than that taught by Lyle, and serves to anchor alubricious organic polymer or wax coating applied to the containersurface after the container exits from the lehr. This combination of tinoxide hot end coating and organic cold end coating has been found usefulin improving the scratch resistance and lubricity of glass containers.

Although this combined coating has been found useful, the generallyemployed methods of applying a hot end coating have several drawbacks.Generally anhydrous compounds, especially anhydrous stannic chloride,were employed which led to numerous problems. First, it was necessary toentrain the tin halide fumes in a dry air stream, which normally isaccomplished by bubbling dry air through a liquid tin halide. Ifmoisture should be introduced into the resulting air stream, aprecipitate results which may inhibit the flow of entrained tin halidefumes, thereby causing a reduction in the amount of coating materialsupplied to the application chamber and which is corrosive to mostmaterials used in the manufacture of the equipment employed.

Next, it is difficult to ensure formation of a uniform 'hot end coatingwhen such a stream is used because the metal halide fumes can react withmoisture in the atmosphere before contacting the glass surface. Theresult is non-uniform coating thicknesses and poor bottle-tobottlereproducibility. Moreover, the loss of metal halide through such areaction seriously reduces the efficiency of the use of the expensivemetal halide reagent. Finally, it is essential to prevent formation of ametal oxide coating on the finish, or mouth, of bottles so as to avoidcorrosion of bottle caps. This control is difficult to achieve with airstreams containing entrained'metal halide fumes, especially with theso-called stubby beer bottles which are commonly employed today.

Although tin oxide coatings, especially those derived from anhydrousstannic chloride, have been most common, efforts have been made toprovide other metal oxide films, notably titanium oxide films, on glass.For

example, Deyrup, in U.S. Pat. No. 2,831,780 issued Apr. 22, 1958,discloses applying vapors of a metalloorganic compound such astetra-isopropyl titanante to hot glass (450600C.). According to Deyrupthe corresponding inorganic compounds are either too heat stable orinsufficiently volatile without decomposition to be suitable for suchuse. Subsequently Gray et al., in U.S. Pat. No. 3,004,863 described aprocess in which aqueous solutions of certain aqueous acid-soluble tita'nates were applied to glass at room temperature and the glass wasthereafter annealed, at which time the titanium oxide coating wasformed. Still more recently, Green et al., in U.S. Pat. No. 3,667,926issued June 6, 1972, disclosed a process wherein an aqueous solution ofa water-soluble titanium composition was sprayed onto hot glass. As wasthe case with Deyrup and Gray et al., Green et al. employed solutions oforgano titanium compounds. Anhydrous titanic chloride has been employedin some instances, notably for coating baby food jars. However, titanicchloride is much more reactive with moisture than stannic chloride, andaccordingly more stringent precautions must be taken. Moreover, theoutlet for the titanic chloride must be extremely close to the glasssurface so that the fumes will react with the glass surface beforereacting with atmospheric moisture.

Despite continued efforts to develop a practical titanium oxide coating,the method of choice today continues to employ the relatively lessexpensive anhydrous tin tetrachloride in preference to the moreexpensive organo metallic titanium compounds or the more difficult touse anhydrous titanic chloride.

BRIEF SUMMARY OF THE INVENTION It is an object of this invention toprovide an improved method for applying a metal oxide coating to a glasssurface.

It is a further object of this invention to provide an improved methodof applying metal oxide hot end coatings to glass containers.

A still further object of this invention is to provide a simple,economical process for applying hot end metal oxide coatings to glasscontainers which is free of the problems associated with the use ofanhydrous metal halide reagents.

Another object of this invention is to provide an economical method forapplying titanium oxide coatings to glass surfaces.

Still another object of this invention is to provide a method foremploying inorganic titanium compounds as the thermally decomposablecompound.

These and other objects of this invention, which are evident from thespecification and claims, are achieved by spraying a solution of atitanium oxychloride onto a heated glass surface. The use of such asolution avoids the need for equipment to afford anhydrous air streamsof stannic chloride and the attendant problems. In particular, airdryers and pressure feed lines necessitated by the use of anhydrousstannic chloride fumes are obviated, and a simple gravity feed systemcan be employed. In addition, the use of a liquid medium affords muchgreater control over the thickness and height of the resulting metal.oxide coating on the container. Because of the greater control, longspraying distances are feasible, thus enabling the use of widerpassageways and minimizing container jam-ups at the hot end applicationstation. Furthermore, titanium oxychlorides can produce equivalentcoatings at considerably lower cost than the anhydrous stannic chloride,and are easier and safer to store than anhydrous tin halides.

The suitability of titanium oxychlorides for this purpose is unexpectedand surprising in light of the difficulties encountered in the use ofanhydrous titanic tetrachloride, the teachings of Deyrup that inorganictitanium compounds cannot be employed, and the continued efforts of theart to develop procedures employing organic titanium compounds.

DETAILED DESCRIPTION The titanium oxychlorides employed in accordancewith this invention may be represented by the formula:

wherein x is l, 2 or 3. Where x is 4 the compound cannot be used toprovide a coating to glass surfaces. These compounds are known, havingbeen described, for example, in Mellor, Inorganic and TheoreticalChemistry, Vol VII, Longman Group Ltd, London (1970) at pages 823.

The titanium oxychloride is employed in accordance with this inventionin the form of an aqueous solution. Suitable solutions are obtained byadding anhydrous titanium tetrachloride to dilute hydrochloric acid toform a concentrated solution of titanium oxychloride. The resultingsolution is further diluted with water prior to use.

The form of the titanium oxychloride which is obtained is determined bythe concentration of the hydrochloric acid and the amount of titaniumtetrachloride added to the acid. For example, the oxychloride wherein xin the above formula is l predominates where titanium tetrachloride isadded up to its solubility limit to an acid solution containing fromabout 25% to about 36% anhydrous hydrogen chloride. The oxychloridewherein x is 2 predominates where the titanium tetrachloride is added upto its solubility limit to a solution containing from about to aboutanhydrous hydrogen chloride. Finally, the oxychloride wherein x is 3predominates when the titanium tetrachloride is added up to itssolubility limit to a solution containing about 10-12% anhydroushydrogen chloride. Intermediate hydrochloric acid concentrations orlesser amounts of titanium tetrachloride yield mixtures of theoxychlorides.

The reaction resulting upon addition of titanium tetrachloride tohydrochloric acid is exothermic, and it is desirable to cool thereaction mixture while adding the titanium chloride to it. In general,it is preferred that the reaction temperature be no greater than roomtemperature (about C.). The amount of cooling required can be minimizedby adding the titanium tetrachloride to the acid slowly, e.g. dropwise,while agitating the reaction mixture.

It is desired that the titanium oxychloride solution produced by theforegoing procedure be as concentrated as possible. The concentrate isthen shipped to the ultimate consumer, e.g. the container manufacturer,who then dilutes the mixture to the desired concentration forapplication to the glass surface.

The concentration of titanium oxychloride in the working solution shouldbe sufficient to provide a coating affording adequate scratch protectionin a reasonable time. Ordinarily, improved scratch resistance isachieved at coating thicknesses at least about 10 CTUs (CoatingThickness Units), with thicknesses of about CTUs or higher preferred.The concentration should not be so high, however, that a metallic sheenor an iridescence is imparted to the bottle surface (unless, of course,such an effect is desired). In general, working solutions containing upto about 4 weight percent titanium tetrachloride equivalents have beenfound useful, with solutions containing from about 0.2 to about 1.5weight percent titanium tetrachloride equivalents being preferred forapplication times of the order of from about 3 to about 5 seconds.(These concentrations correspond to up to about 3.6 weight percent asTi(OI-I)Cl and from about 0.1 weight percent as Ti- (OI-I) Cl to about1.4 weight percent as Ti(OI-I)Cl The dilute titanium oxychloridesolution is applied to hot glassware, e.g. virgin containers just priorto annealing in the lehr, by conventional techniques. It is desired,however, that a high degree of atomization of the aqueous solution beemployed to provide an acceptable appearance. That is, unless thesolution is sufficiently finely divided, the surface of the treatedglassware will leave blemishes which resemble water spots. A suitablelevel of atomization can be determined by spraying the solution onto acool bottle and then counting the number of droplets deposited on thesurface in, e.g. a 0.1 inch square, and then calculating the number ofdroplets per square inch. It has been found that satisfactory resultsare achieved when spraying bottles if the degree of atomization issufficient to provide at least 4000 droplets per square inch.

The aqueous titanium oxychloride is applied to heated glass, e.g.freshly formed glass containers prior to annealing in a lehr. It hasbeen unexpectedly and surprisingly found, however, that temperaturesbelow those employed in prior art processes are feasible with thepresent process. For example, tin tetrachloride commonly is applied toglassware at temperatures of 900 to 1500F. In contrast, temperatures offrom about 300 to about 800F. have been found optimum when employingaqueous titanium oxychloride solutions. Coating thickness is relativelyindependent within this range of temperatures, and thus uniform coatingsare readily achieved despite fairly large variations of glasstemperature so long as the temperature is within this temperature range.Moreover, the most efficient usage of the oxychloride solution, i.e. thecoating thickness achieved per unit volume of aqueous titaniumoxychloride solution is maximized, at temperatures within the range.Finally, superior coating appearance is achieved at temperatures withinthis range when compared with the appearance of coatings of comparablethickness obtained at higher or lower temperatures.

Because relatively low temperatures can be employed, the titaniumoxychloride can be incorporated into the cold end spray applied tobottles after they are removed from the annealing lehr, provided thebottle temperature is greater than about 300F., and preferably is around500F. The particular cold end coating material is not critical, andvarious waxes, polymer coatings such as polyethylene and the like areknown and are useful. These materials normally are supplied as aqueousemulsions which can be admixed with the aqueous titanium oxychloride.Since the titanium oxychloride is acidic, the emulsion must be one whichis stable in acidic media. Accordingly, emulsions prepared withnon-ionic emulsifying agents are preferred. In such solutions theconcentration of the organic coating material can be the same as thatwhen the organic material is employed alone, e. g. from about 0.1 toabout 0.5 weight percent of the solution.

. 1 The following examples are illustrative of this inverttion. In theexamples, the following test procedures were employedi V l. CoatingThickness The thickness of the coating achieved with the titaniumoxychloride was measured with a Hot End Coating Meter manufactured byAmerican Glass Research, Inc. and is reported in CTUs[l CT U (CoatingThickness Unit) is approximately equal to l Angstrom].

2. Lubricity The lubricity of the coating achieved extent of surfacedamage produced during sliding contact when tested under a given load.Usually this value is expressed as a load in pounds under which.

continuous surface damage was produced during sliding contact. [SeeGlass Container Manufacturers Institute, Inc. Technical Bulletin No.69].

All parts and percentages are by weight unless other wise specified.

EXAMPLE I Several series of experiments were performed to evaluate theeffect of coating thickness and application temperature upon coatinglubricity and scratch resistance achieved with aqueous titaniumoxychloride.

In the first series, l2-ounce, amber handy beer bottles were heated toll00F. in a muffle furnace and then placed in a series of furnaces at1000F., 800F., 700F. and 350F. for varying lengths of time to simulatean annealing lehr. When the temperature of the bottles had fallen to300F., as measured by an Ircon Model 710 infra-red detector, the bottleswere placed on a turntable and aqueoustitanium oxychloride solutionsformed by adding parts of titanium tetrachloride to 50 parts 'of 50%hydrochloric acid to form a stock solution and subsequently dilutingtoform a solu tion of the desired concentration, were applied by a Binksmodel 16, internal mix spray gun for l revolution of the bottle(approximately 3 seconds). The concentration of the titanium oxychlorideranged from 0.09% to 4.2%, calculated as titanium tetrachloride, andprovided coatings having thicknesses of up to about 55 ClUs. For eachsolution concentration, and hence for each coating thickness, 6 bottleswere prepared.

After the bottles had cooled to 250F. they were over-coated with a 0.27weight percent dispersion of polyethylene in water with thespray gunthrough one revolution of the turntable.

Each of the resulting bottles was divided into three areas for testing,one area to be tested dry, one to be tested wet and one to be tested wetfollowing a caustic wash (30 minutes at 150F. with an aqueous solutionof 4.5% sodium hydroxide and 0.5% trisodium phos phate) and heating inan autoclave at psi and 250F. for 60 minutes.

For each coating thickness, the 6 bottles were paired and, after storagefor 24 hours, each pair was treated for scratch resistance and lubricityat 15 and 60 pounds load.

During each test, a trace of the coefficient of friction wasmade and theaverage maximum value was determined for each pair of samples. The metaloxide thickness was then measured for both bottles of each pair at 10locations around the track area for a given test condition and load. Themeasuremer s for each bottle were averaged and the minimum average valueof a pair for a given load and condition was calculated.

In the second series of experiments, the procedure was repeated, exceptthat the bottles were removed from the 700F. furnace and the titaniumoxychloride solution was applied at 600F. and the bottles were placed inthe 350F. furnace to complete the cycle.

In the third and fourth series, the bottles were allowed to cool to800F. or IO50F., respectively, upon removal from the muffle furnace, thetitanium oxychloride solutions were applied, the bottles were thenpassed through the annealing cycle, the organic coating was applied andlubricity and scratch resistance were determined.

In general, goodlubricity (maximum average coefficient not greater thanabout 0.1) was obtained in the dry and wet scratch, tests at 15 and 60pound loads for all coatings in excess of 20 CTUs for all applicationtemperatures, and no bottle damage was observed for coating thicknessesof 30 CTUs or higher. However, coatings of less than 2030 CTUs formed at1050F. had materially higher coefficients of friction and/0r exhibitedsurface damage.

Similar results were observed after the caustic wash and autoclavetreatment, except that at the 60 pound load level, surface damage wasobserved on all bottles having coating thicknesses of not greater thanabout 20 CTUs, except those coated at 600F., which were acceptable atthicknesses as low as 10 CTUs. Coefficients of friction were allconsiderably higher than in the other tests, and did not reach a minimumvalue (of about 0.1) until thicknesses of at least 20-30 CTUs wereachieved.

Based upon the results of these experiments, it was concluded thatoptimum results are achieved with an aqueous titanium oxychloridesolution of sufficient.

concentration to provide a coating thickness of at least about 30 CTUs.At this level, lubricity and scratch resistance are independent ofapplication temperature. However, satisfactory lubricity and scratchresistance are achieved at lower thicknesses (10-20 CTUs) if theapplication temperature is about 600F.

EXAMPLE II Solutions of titanium oxychloride and polyethylene wereevaluated as protective lubricious coatings applied in the cold end byfirst heating l2-ounce amber handy bottles in a muffle furnace to thedesired application temperatures (300F., 400F. or 500F.) and allowingthe bottles to soak for 15 minutes to assure uniform glass surfacetemperature. The bottles were then removed from the furnace, placed on arevolving turntable and, when the surface temperature of the bottles hadreached the desired temperature, as measured by an Ircon Model 710Infra-red detector, the coating solution was applied by a Binks Model 16internal mix spray gun for the length of time of l revolution(approximately 3 seconds). Nine solutions were evaluated in which thetitanium oxychloride concentration of the solution was 0.27%, 0.5% or0.8% and the polyethylene concentration of the solution was 0.21%, 0.27%or 0.33%*.

*The polyethylene was added in the form of an aqueous emulsion soldtions for at least 24 hours and tested f coating hi by New JerseySpecialty Chemicals under the trade-designation SC- 1 b d h t 100. andis a 21% solids emulsion of an ethylene copolymer (Allied 355, u ncltyan scram resls ance- Chemical 540 P y ylene). The data from these testsare summarized as follows:

The bottles were then stored under ambient condi- TABLE I Lubricity andScratch Resistance Results* (0.27% of Solution Oxychloride) Tested WetFollowing Solution Tested Dry Tested Wet Caustic Wash AutoclaveConcentration Application t TLmax.D IZmax.-D TLmax.-D

as SC-lOO Temperature (CTU's) l5 lbs. 60 lbs. l5 lbs. 60 lbs. lbs. 60lbs.

.2l% 300F .l-i l lO-i .O75-N .l25-N .l30-N .l-i 2O .lUO-i .099-N .O80-N.O90-N .230-i .ZOO-i 400F 33 .lSO-N l lO-N .090-N .O70-i .l-i .ZIO-C 25.l l l-N .l05-i .O90-N .O85-N .l20-N .260-C 500F 29 .l20-N .l l3-i.OSO-N lOO-i .l40-N .ZZO-C .277c 300F l8 .1 lO-N 10-1 .O70-N .O80-i.390-i .350-C 29 IOO-i .O95-N .O70-N .l lO-i l 70-N .260C 4OO 'F 2O lO-N.l l5-i .O-N .O80 N .l35-N .1804 26 .lO5-N .lOO-i .O-N .l lO-i .lZO-N.lZO-i 500F 25 .lOO-N .lO3-i .O70-N .l40-C .l30-N .205-C 33% 300F 2O.O90-N .080-i .O60-N .O-N .270-N .260-C 2O .O88-N .l lO-C .O60-N .O-i.ZSO-i .260-C 400F 24 .O93-N .0994 .OSl-N .O59-N .l lO-N .330-C 2O.lOO-N .O-N .065-N .O75-N .220-N .340-C 500F 23 .lOO-N .095-i .O60-N.O70-i .l55-N .l50-i *D Glass surface damage N None i isolated crescentcracks C continuous damage Ttmax. average maximum coefficient offriction. t,,,,,. average minimum thickness TABLE II Lubricity andScratch Resistance Results* (0.5% of Solution Oxychloride) Tested WetFollowing imax. average maximum coefficient of friction tminl averageminimum thickness *D Glass surface damage N None i Isolated crescentcracks C Continuous damage .fimax. average maximum coefficient offriction trnin. average minimum thickness As is evident from Table l,the metal oxide level for all temperatures and organic concentrations at0.27% titanium oxychloride is between approximately -30 CTUs. Thelubricity and scratch resistance results show a poor degree of filmperformance for bottles tested at a 60 pound load after a caustic washand autoclave pretreatment.

Table II, which summarizes the test results of solutions employing 0.5%titanium oxychloride, shows the expected increase in metal oxidethickness as the percentage of oxychloride in solution is increased.Also, the lubricity and scratch resistance values indicate a higherdegree of film performance than those samples reported in Table I.Generally, the best performance characteristics were obtained for anapplication temperature of 500F. employing either 0.27% or 0.33% of thespray solution as SC-lOO polyethylene.

Table III summarizes the test results with the solutions containing 0.8%titanium oxychloride, and shows a slight increase in the metal oxidethickness corresponding to the change in oxychloride concentration.However, there appears to be no change in the film performance over theresults summarized in Table II.

What is claimed is:

1. In a method for applying an in-organic titaniumcontaining coating toa glass surface comprising exposing said surface to athermally-decomposable titanium compound at an elevated temperaturesufficient to cause thermal decomposition of said compound to form saidcoating, the improvement wherein said coating is formed by spraying ontosaid surface a finely divided dilute aqueous solution of a titaniumoxychloride of the formula Ti(Ol-l CI wherein x is l, 2, or 3, saidtemperature ranging from about 300F. to about 800F.

2. The method according to claim 1 wherein the concentration of saidtitanium oxychloride in said solution is up to about 4 weight percent,calculated as titanium tetrachloride.

3. The method according to claim 1 wherein the degree of atomization ofsaid spray is sufficient to provide at least 4000 droplets per squareinch at the glass surface.

4. In a method for imparting improved scratch resistance and lubricityto a glass container comprising applying an inorganictitanium-containing coating and a lubricous organic coating to the outersurface of said container, said titanium-containing coating being formedby applying a thermally-decomposable compound to the surface of saidcontainer at an elevated temperature sufficient to cause thermaldecomposition of said compound to form said coating, the improve mentwherein said inorganic coating is formed by spraying a finely divideddilute aqueous solution of a titanium oxychloride of the formulaTi(OH),Cl wherein x is l, 2 or 3, onto said container, said temperatureranging from about 300F. to about 800F.

5. The method according to claim 4 wherein the concentration of saidtitanium oxychloride in said solution is up to about 4 weight percent,calculated as titanium tetrachloride.

6. The method according to claim 4 wherein said aqueous solution isapplied to virgin containers just prior to annealing.

7. The method according to claim 4 wherein said solution includes anorganic lubricous coating material and said solution is applied to saidcontainer surface after annealing and at a temperature of from about300F. to about 500F.

8. The method according to claim 4 wherein the degree of atomization ofsaid spray is sufficient to provide at least 4000 droplets per squareinch at the glass surface.

1. IN A METHOD FOR APPLYING AN IN-ORGANIC TITANIUM-CONTAINING COATING TOA GLASS SURFACE COMPRISING EXPOSING SAID SURFACE TO ATHERMALLY-DECOMPOSABLE TITANIUM COMPOUND AT AN ELEVATED TEMPERATURESUFFICIENT TO CAUSE THERMAL DECOMPOSITION OF SAID COMPOUND TO FORM SAIDCOATING, THE IMPROVEMENT WHEREIN SAID COATING IS FORMED BY SPRAYING ONTOSAID SURFACE A FINELY DIVIDED DILUTE AQUEOUS SOLUTION OF TITANIUMOXYCHLORIDE OF THE FORMULA TI(OH)XCL(4-X), WHEREIN X IS 1, 2, OR 3, SAIDTEMPERATURE RANGING FROM ABOUT 300F. TO ABOUT 800*F.
 2. The methodaccording to claim 1 wherein the concentration of said titaniumoxychloride in said solution is up to about 4 weight percent, calculatedas titanium tetrachloride.
 3. The method according to claim 1 whereinthe degree of atomization of said spray is sufficient to provide atleast 4000 droplets per square inch at the glass surface.
 4. IN A METHODFOR IMPARTING IMPROVED SCRATCH RESISTANCE AND LUBRICITY TO A GLASSCONTAINER COMPRISING APPLYING AN INORGANIC TITANIUM-CONTAINING COATINGAND A LUBRICOUS ORGANIC COATING TO THE OUTER SURFACE OF SAID CONTAINER,SAID TITANIUMCONTAINING COATING BEING FORMED BY APPLYING ATHERMALLYDECOMPOSABLE COMPOUND TO THE SURFACE OF SAID CONTAINER AT ANELEVATED TEMPERATURE SUFFICIENT TO CAUSE THERMAL DECOMPOSITION OF SAIDCOMPOUNT TO FORM SAID COATING, THE IMPROVEMENT WHEREIN SAID INORGANICCOATING IS FORMED BY SPRAYING A FINELY DIVIDED DILUTE AQUEOUS SOLUTIONOF A TITANIUM OXYCHLORIDE OF THE FORMULA TI(OH)XCL(4-X), WHEREIN X IS 1,2, OR 3, ONTO SAID CONTAINER, SAID TEMPERATURE RANGING FROM ABOUT 300*F.TO ABOUT 800*F.
 5. The method according to claim 4 wherein theconcentration of said titanium oxychloride in said solution is up toabout 4 weight percent, calculated as titanium tetrachloride.
 6. Themethod according to claim 4 wherein said aqueous solution is applied tovirgin containers just prior to annealing.
 7. The method according toclaim 4 wherein said solution includes an organic lubricous coatingmaterial and said solution is applied to said container surface afterannealing and at a temperature of from about 300*F. to about 500*F. 8.The method according to claim 4 wherein the degree of atomization ofsaid spray is sufficient to provide at least 4000 droplets per squareinch at the glass surface.